Hi All, A follow up question. Is there a way to view the combined XML? I am constantly missing elements not knowing if it is my paths or my original files or the combiner.
Thanks, On Sun, Nov 13, 2016 at 2:54 PM, Greg Torrance <greg.torra...@pobox.com> wrote: > Thanks Oliver. > > I think I understand what you're saying about why Channel 4 would not be > included with the OverrideCombiner (if it doesn't exist in testfile1.xml). > I am sorry to hear, though, that attributes are not used at all for > matching with OverrideCombiner. If I'm understanding it correctly, that > means it can't really be used for overriding just specific list items, as > the entire list would have to be represented, in the same order, in both > primary and overriding files, or the wrong list item might be overridden. > (For example, if the primary list had Channels 1, 2, and 3, and the > override list had only Channel 2, then it would attempt to override Channel > 1 with the info from Channel 2.) Is my understanding correct? > > Anyway, I'm going to experiment a bit and try to make sure I have a good > understanding of how this works. > > Thanks again for the help. > > Greg > > > On 11/13/2016 01:51 PM, Oliver Heger wrote: > >> Hi Greg, >> >> Am 13.11.2016 um 18:41 schrieb Greg Torrance: >> >>> Hi Oliver, >>> >>> Thanks for the reply. That is helpful! >>> >>> Hm, it looks as if the examples are partly incorrect. I assume that >>>> >>> the channel with id="4" should not be part of testfile1.xml, but only be >>> contained in the second file. It should appear in the results of union >>> and merge combiner. Does that make sense? >>> >>> I'm not clear why -- if the channel with id="4" is not contained in >>> testfile1.xml -- why it will not end up in the results from all three >>> combiners. Why just union and merge and not override, too? >>> >> On a higher level, OverrideCombiner detects that both files have a list >> of channels. Therefore, it copies the first list and ignores the second >> one. So the channels element in the first file overrides the one in the >> second file. >> >> As for the attributes, do I understand correctly that the attribute >>> values for elements are used, essentially, as "key" values to >>> distinguish the various elements for combining purposes? And if the >>> values of any attributes of two elements differ, then the elements would >>> be considered different elements for combining purposes? (Said another >>> way, if two elements have a set of attributes in common, if the values >>> for those common attributes are the same, the elements will be >>> considered to match.) Does that make sense? Is that correct? >>> >> This is true only for MergeCombiner. The other combiners do not try to >> match nodes in both configurations based on their attribute values; they >> take two source nodes at the same position in the hierarchy and produce >> a result node that has all the attributes of the two source nodes. >> >> Oliver >> >> Thanks again for the reply. >>> >>> Greg >>> >>> On 11/13/2016 12:05 PM, Oliver Heger wrote: >>> >>>> Hi Greg, >>>> >>>> Am 13.11.2016 um 15:07 schrieb Greg Torrance: >>>> >>>>> Hi all, >>>>> >>>>> I am trying to work out the precise differences between >>>>> OverrideCombiner, UnionCombiner, and MergeCombiner. However, the >>>>> examples on this page >>>>> (https://commons.apache.org/proper/commons-configuration/use >>>>> rguide/howto_combinedconfiguration.html) >>>>> >>>>> are confusing to me. >>>>> >>>>> testfile1.xml and testfile2.xml both contain Channels with id="4", >>>>> however none of the Combiner Results shows any Channels with id="4". >>>>> And the Notes on the right-hand side of the page contain no mention of >>>>> Channel 4. >>>>> >>>>> Am I missing something? Are the examples correct? >>>>> >>>> Hm, it looks as if the examples are partly incorrect. I assume that the >>>> channel with id="4" should not be part of testfile1.xml, but only be >>>> contained in the second file. It should appear in the results of union >>>> and merge combiner. Does that make sense? >>>> >>>> What I'm really trying to understand is the impact of attributes in the >>>>> way the various combiners choose to combine elements. (Any pointers to >>>>> further documentation on this would be appreciated.) >>>>> >>>> Some more information can be found in the Javadocs of the combiner >>>> classes: >>>> - UnionCombiner states: "Another limitation is the handling of >>>> attributes: Attributes can only have a single value. So if two nodes are >>>> to be combined which both have an attribute with the same name, it is >>>> not possible to construct a proper union attribute. In this case, the >>>> attribute value from the first node is used." >>>> >>>> - OverrideCombiner has an addAttributes() method with the following >>>> documentation: "Handles the attributes during a combination process. >>>> First all attributes of the first node are added to the result. Then all >>>> attributes of the second node, which are not contained in the first >>>> node, are also added." >>>> >>>> - The merging behavior of MergeCombiner is also described in its class >>>> documentation. >>>> >>>> Does this help? >>>> Oliver >>>> >>>> Thoughts? >>>>> >>>>> Thanks, >>>>> Greg >>>>> >>>>> >>>>> --------------------------------------------------------------------- >>>>> To unsubscribe, e-mail: user-unsubscr...@commons.apache.org >>>>> For additional commands, e-mail: user-h...@commons.apache.org >>>>> >>>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: user-unsubscr...@commons.apache.org >>>> For additional commands, e-mail: user-h...@commons.apache.org >>>> >>>> >>>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: user-unsubscr...@commons.apache.org >>> For additional commands, e-mail: user-h...@commons.apache.org >>> >>> --------------------------------------------------------------------- >> To unsubscribe, e-mail: user-unsubscr...@commons.apache.org >> For additional commands, e-mail: user-h...@commons.apache.org >> >> >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@commons.apache.org > For additional commands, e-mail: user-h...@commons.apache.org > >
